EP3427356B1

EP3427356B1 - Racking interlocking systems for withdrawable circuit breakers

Info

Publication number: EP3427356B1
Application number: EP17705762.7A
Authority: EP
Inventors: Przemyslaw Eugeniusz Cieply; Ryszard RZEPECKI; Andrew Matthew Candelora; Nagesh Venkata Tumu; Szymon WASIK; Alisha Marie DAVIS
Original assignee: ABB Schweiz AG
Current assignee: ABB Schweiz AG
Priority date: 2016-03-09
Filing date: 2017-02-08
Publication date: 2022-03-30
Anticipated expiration: 2037-02-08
Also published as: CN109716606A; EP3427356A1; US20170264085A1; CN109716606B; US9843174B2; WO2017155654A1

Description

BACKGROUND

The field of the disclosure relates generally to power equipment and, more particularly, to a locking mechanism for use with power equipment.
Electrical systems, such as power generation, power transmission, power distribution, and power conversion systems, often include switchgear used to control, protect, and/or isolate electrical equipment within the electrical system. Switchgear often serves as connectors between power supplies and power loads to protect and control low voltage circuits. Switchgear generally includes a switch cabinet that houses a switch unit that includes bus bars, electrical cables, circuit breakers, electrical switches, and/or fuses electrically connected in a desired manner to control, protect, and/or isolate the electrical equipment of electrical systems. Circuit breakers generally include contact arms and a trip mechanism coupled together to open the current path in case of a fault detection. The contact arms in circuit breakers are used to close the current path within the breaker. Once the circuit is closed, power flows through the breaker.
At least some known circuit breakers include terminals that are permanently coupled to the busbar system within the switchgear cabinet. Some such breakers include draw-out units that are used to provide an option to remove the breaker from the cabinet for servicing without disconnecting the draw-out unit from the switchgear. At least some known circuit breakers, for example, generally use external locking mechanisms to prevent the carriage assembly from being installed or "racked in" within the switchgear to a service position. For example, at least some known circuit breaker carriage assemblies use a system of gears to facilitate inserting circuit breaker to a service position within the switchgear or to partially withdraw from the switchgear the circuit breakers to a test position. To prevent the circuit breaker from being racked in and receiving power during service, a brake may be provided that engages the gear system. Moreover, some known circuit breaker carriage assemblies use covers, such as switch covers, that prevent the circuit breaker from receiving power during service. Other known circuit breaker carriage assemblies can include a block or stopper that prevents the circuit breaker from being racked in. However, additional parts, such as brakes, covers, padlocks, and/or blocks can be lost or damaged during transport or in storage. Moreover, each of these mechanisms is external to the circuit breaker and/or the carriage assembly, which can lead to damage during use. Accordingly, it is desirable to provide a locking mechanism that is internal to the carriage assembly and does not require additional separate parts.
US 2777024 , on which the preamble of claim 6 is based, discloses a draw-out circuit breaker assembly including a circuit breaker having a plurality of contacts and an interlocking system, said interlocking system comprising: a racking screw coupled to the plurality of contacts that changes a position of the circuit breaker within the draw-out circuit breaker assembly when engaged by a tool; a front panel defining an opening through which said racking screw is selectively accessible; an access door coupled to said front panel and configured to selectively cover the opening to selectively provide access to said racking screw; and an access door stopper configured to limit movement of said access door based on a position of the plurality of contacts.
EP 1231691 discloses a tripping device for a circuit breaker in connection with an extension device in which a line switch mounted on a slide can be moved. To achieve this, a spindle drive can be driven on the one hand by an attachable drive mechanism and on the other is in operative connection with the slide via lateral drive means. The tripping device contains first release means connected to the power switch and having an unlatching effect on its actuating mechanism, and second release means connected to the extension device.
US 4728757 discloses an interlock for preventing access to a draw-out mechanism of a draw-out circuit breaker which is in a contact "closed" position and preventing the contacts from being closed when the circuit breaker is only partially connected to the power bus. A sliding door, carried by the front cover of the circuit breaker, is movable between a first position providing access to a driver shaft assembly for operation of the draw-out mechanism and a second position preventing access to the driver shaft assembly. A plunger and slider assembly is operably associated with the access door to prevent the door from being moved from the second position to the first position unless the contacts within the circuit breaker are open. A trip arm prevents the contacts from being closed when the circuit breaker is only partially connected to the power bus.

BRIEF DESCRIPTION

According to a first aspect of the invention, there is provided a method of assembling a draw-out breaker assembly including a circuit breaker having a plurality of contacts, said method comprising: coupling an interlocking system to a front panel of a base assembly, wherein coupling the interlocking system comprises: coupling an access door to the front panel such that the access door selectively covers an opening formed in the front panel; coupling an access door stopper to the front panel and to the access door, wherein the access door stopper is selectively moveable between a trip position and an open position; and coupling a racking screw to the front panel and to the plurality of contacts; coupling a trip assembly to the front panel and to the access door stopper, wherein the trip assembly is selectively moveable between a rest position, a trip position and an open position, such that, when (i) the access door stopper is in the trip position, (ii) the trip assembly is moved from the rest position to the trip position by the access door stopper to engage a trip bar of the circuit breaker, and (iii) the access door is partially opened such that access to the racking screw through the opening is prevented, a mechanical trip signal is provided to the circuit breaker to position the plurality of contacts in the open position, and such that, when (i) when the access door stopper is moved to the open position, (ii) the trip assembly is moved to the open position by the access door stopper, and (iii) the access door is fully opened to enable access to the racking screw, the open position of the plurality of contacts is confirmed.
According to a second aspect of the invention, there is provided a draw-out circuit breaker assembly including a circuit breaker having a plurality of contacts and an interlocking system, said interlocking system comprising: a racking screw coupled to the plurality of contacts that changes a position of the circuit breaker within the draw-out circuit breaker assembly when engaged by a tool; a front panel defining an opening through which said racking screw is selectively accessible; an access door coupled to said front panel and configured to selectively cover the opening to selectively provide access to said racking screw; and an access door stopper configured to limit movement of said access door based on a position of the plurality of contacts; characterized in that said access door stopper is coupled to and at least partially extends through said front panel; and in that said interlocking system further comprises a trip assembly coupled to said access door stopper, wherein said access door is moveable between a trip position and an open position, wherein said access door stopper is moveable between a rest position, a trip position and an open position, and wherein said trip assembly is moveable between a rest position, a trip position and an open position, wherein moving said access door to the trip position, said access door stopper from the rest position to the trip position, and said trip assembly from the rest position to the trip position triggers delivery of a mechanical trip signal to the circuit breaker to open the plurality of contacts, wherein, in the open position, the access door is fully open to enable access to said racking screw through said front panel, wherein, in the trip position, the access door is partially open to prevent access to the racking screw through the opening, and wherein movement of the access door stopper and the access door to the open position is only possible when the plurality of contacts are open.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary draw-out breaker assembly;
FIG. 2 is a perspective view of the draw-out breaker shown in FIG. 1 with the breaker removed illustrating an exemplary base assembly;
FIG. 3 is a perspective view of an exemplary racking system that may be used with the draw-out breaker assembly shown in FIG. 1;
FIG. 4A is a front perspective view of an exemplary interlocking system of the draw-out breaker assembly shown in FIG. 1 in a rest position;
FIG. 4B is a rear perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 in the rest position;
FIG. 5 is a front perspective view of an exemplary trip interface of the draw-out breaker assembly shown in FIG. 1;
FIG. 6 is a front perspective view of the trip interface of the draw-out breaker assembly shown in FIG. 1;
FIG. 7 is a front perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 in the rest position;
FIG. 8A is a front perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 in a trip position;
FIG. 8B is a rear perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 in the trip position;
FIG. 9A is a front perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 in the trip position when the contacts of the breaker are in the open position;
FIG. 9B is a rear perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 in a trip position when the contacts of the breaker are in the open position;
FIG. 10 is another perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 in a trip position when the contacts of the breaker are in the open position;
FIG. 11A is a front perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 in a trip position when the contacts of the breaker are in the open position and the breaker is locked;
FIG. 11B is a rear perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 in a trip position when the contacts of the breaker are in the open position and the breaker is locked;
FIG. 12A is a front perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 when the breaker is between the test and connected position; and
FIG. 12B is a front perspective view of the interlocking system of the draw-out breaker assembly shown in FIG. 1 when the breaker is between the test and connected position.

DETAILED DESCRIPTION

Exemplary embodiments of apparatuses are described herein for use in preventing power from being applied to devices, such as a circuit breaker, when the devices are not fully engaged within a draw-out assembly. These embodiments facilitate safer operation of a circuit breaker. The systems, method, and apparatus described herein facilitate a method for racking a circuit breaker in a draw-out breaker assembly. In particular, the systems, method, and apparatus described herein include an interlocking system that provides a trip signal to the circuit breaker to position a plurality of breaker contacts in an open position. To provide the trip signal, the interlocking system is moved to a trip position. More specifically, an access door stopper is actuated to the trip position, which causes an access door to partially open preventing access to a racking screw, and also causes actuation of a trip assembly to the trip position to engage and rotate a trip bar of the circuit breaker to facilitate tripping the breaker and opening the contacts.
Furthermore, the interlocking system verifies the position of the contacts to confirm that the contacts are indeed open and that a failure has not occurred. In the event of a failure, a contacts position indicator of the interlocking assembly moves from an open position to a failure position and extends from the breaker into the path of the trip assembly. To verify the position, the interlocking system is moved to an open position. More specifically, the access door stopper is actuated to the open position, which causes actuation of a trip assembly to the open position. If there is no failure and the contacts are open, then the trip assembly moves past and does not contact the contacts position indictor, and the access door is able to fully open allowing access to the racking screw. If there has been a failure and the contacts are closed, the trip assembly will contact the contacts position indicator and prevent trip assembly from further actuation, which prevents the access door from fully opening, therefore preventing access to the racking screw.
FIG. 1 is a perspective view of an exemplary draw-out breaker assembly 100 including a circuit breaker 102 and a base assembly 104. FIG. 2 is a perspective view of draw-out breaker assembly 100 with breaker 102 removed illustrating base assembly 104. In the exemplary embodiment, breaker 102 is coupled to base assembly 104 by a first side sheet 106 and an opposing second side sheet 108. Breaker 102 is removable from base assembly 104 and from a main power circuit (not shown) without requiring disassembly of the fixed connection between breaker connection terminals and a busbar system (not shown) of the main power circuit. Side sheets 106 and 108 are positioned on either side of breaker 102 and facilitate withdrawal of breaker 102 from base assembly 104. In the exemplary embodiment, base assembly 104 includes a base 110 including a plurality of connection terminals 112, a plurality of shutters 114, and a plurality of shutter covers 116. Shutters 114 cover terminals 112 to protect against access to electrically live components when breaker 102 is removed from base assembly 104. Base assembly 104 also includes a first side plate 118 and an opposing second side plate 120, which are both coupled to base 110 on either side of breaker 102 outside of side sheets 106 and 108. Side plate 120 includes a height adjustment system 122 and a front panel 124, the height of which is adjustable using height adjustment system 122.
FIG. 3 is a perspective view of an exemplary racking system 126 that may be used with draw-out breaker assembly 100. In the exemplary embodiment, racking system 126 is coupled to second side plate 120 and includes a racking screw 128, a racking screw nut 130, and a cross shaft 132 having a racking cam 134. Rotational movement of racking screw 128 causes linear movement of racking screw nut 130 on racking screw 128 itself, which causes rotation of cross shaft 132. Cam 134 is coupled to cross shaft 132 and are engaged with side sheets 106 and 108 (shown in FIG. 1) such that rotation of cross shaft 132 causes rotation of cam 134 to facilitate racking in or racking out of breaker 102, depending on the direction of racking screw 128 rotation.
FIG. 4A is a front perspective view of an exemplary interlocking system 136 of draw-out breaker assembly 100 in a rest position, and FIG. 4B is a rear perspective view of interlocking system 136 in the rest position. In the exemplary embodiment, interlocking system 136 includes a plurality of mechanically linked cams that enable mechanical interlocking of rack-in/out operation. Interlocking system 136 prevent engagement/disengagement of the main circuit while the main contacts of withdrawable breaker 102 (shown in FIG. 1) are closed. Once the main contacts of breaker 102 are closed, the operator has no access to racking screw 128, and, therefore, breaker 102 cannot change its position with respect to draw-out base assembly 104.
In the exemplary embodiment, interlocking system 136 includes a position indication link 138 that is engaged by racking nut 130 (shown in FIG. 3) to provide the operator with a visual indication of the position of breaker 102 within draw-out assembly 100. Interlocking system 136 also includes a racking access door 140 coupled to front panel 124 to selectively cover an opening defined in the front panel. Interlocking system 136 also includes an access door stopper 142 coupled to and partially extending through front panel 124. Access door stopper 142 is coupled to access door 140 and limits movement of access door 140. In the rest position, as described in further detail below, stopper 142 prevents access door 140 from opening to prevent access to racking screw 128 through an opening 141. When racking access door stopper 142 is pressed in from the rest position, stopper 142 provides a trip signal to breaker 102 and at the same moment releases racking access door 140, thus providing access to racking access screw 128. A locking cam 144 is engaged to and driven by position indication link 138 and facilitates locking access door stopper 142 in an activated position to provide a permanent trip signal to breaker 102. In such a configuration, the breaker contacts cannot be closed.
Furthermore, interlocking system 136 includes a trip assembly including a trip link 146, an actuation slider 148, and an actuation cam system 150. Trip link 146 is mechanically coupled to racking access door stopper 142 and transfers movement of the racking access door stopper 142 to actuation slider 148. Activation slider 148, in turn, activates actuation cam system 150 to provide a trip signal to breaker 102 when it is required to open the breaker contacts prior to racking of breaker 102 inside draw-out base assembly 104.
In the exemplary embodiment, interlocking system 136 also includes a locking link or padlock slider 152 coupled to a lever link or intermediate lever 154 that allows breaker 102 to be locked only when the breaker contacts are open. Locking of draw-out assembly 100 can be executed in two ways: 1) by installing padlocks on padlock slider 152; or 2) by using a key-lock 156 with a corresponding key lock latch 158 that hold intermediate lever 154 in the locked position. When draw-out assembly 100 is locked, a permanent trip signal is provided to breaker 102 that prevents the breaker contacts from being closed.
FIG. 5 is a perspective outside view of an exemplary trip interface 160 of breaker 102, and FIG. 6 is a perspective inside view of trip interface 160. In the exemplary embodiment, trip interface 160 is a component of breaker 102 and includes a trip bar 162, a trip bar extension 164, and an actuator 166. Actuation cam system 150, which is driven by other components of interlocking system 136, engages trip bar extension 164 to cause rotation of trip bar 162 within breaker 102. Rotational movement of trip bar 162 causes linear movement of actuator 166 that acts on a breaker mechanism 168 to trip breaker 102, causing the breaker contacts to open. When trip bar 162 is held in its activated position, a permanent trip signal is provided to breaker mechanism 168, which prevents closure of the breaker contacts. In such a configuration, when the breaker contacts are open, a contacts position indicator 170 is withdrawn inside breaker 102 and allows a slider 172 to move up to enable full rotation of actuation cam system 150.
If the breaker contacts didn't open after providing a trip signal to breaker mechanism 168 (failure mode), slider 172 cannot move up, and full rotation of the actuating cams system 150 is not possible, and full movement of racking access door stopper 142 is prevented. In such a case, racking access door 140 cannot be opened such that access to racking screw 128 is prevented and breaker 102 position inside draw-out assembly 100 cannot be changed, thus eliminating the risk of electric shock to the operator.
FIG. 7 is a front perspective view of interlocking system 136 of draw-out breaker assembly 100 in the rest position 200. Referring also to FIGS. 4A and 4B, in its rest position 200, components of racking interlocking system 136 in front panel 124 do not act on trip bar extension 164 coupled to trip bar 162. As such, breaker 102 can be fully operated, that is, the breaker contacts can change position (can be either open or closed). Racking access door stopper 142 protrudes out of front panel 124 and can be operated (pressed-in) by the operator. In the case that the breaker contacts are closed, contacts position indicator 170 protrudes out from breaker 102.
FIG. 8A is a front perspective view of interlocking system 136 a trip position 300, and FIG. 8B is a rear perspective view of interlocking system 136 in trip position 300. Once an operator wants to change position of breaker 102 inside draw-out assembly 100, racking screw 128 needs to be accessed. To access racking screw 128, racking access door stopper 142 needs to be moved to the trip position, more specifically, stopper 142 is pressed in to front panel 124 to unlock racking access door 140. Movement of racking access door stopper 142 is translated through the trip assembly, and more specifically, through tripping linkage 146 to actuation slider 148. As such, moving stopper 142 into the trip position causes movement of the trip assembly to the trip position. Sliding of actuation slider 148 results in movement of actuation cam system 150 that engages and acts on trip bar extension 164. Trip bar 162 rotates as a result and trips breaker mechanism 168 through actuator 166, thus opening the breaker contacts.
To trip breaker 102, only half of the stroke of racking access door stopper 142 is required. In such a configuration, racking access door 140 is still blocked in such a way that it cannot be fully opened and access to racking screw 128 is prevented. As such, a second step, which is positive result of verification of the breaker contacts state, is required, as described herein.
If breaker 102 is properly tripped (no failure mode, breaker contacts were open), contacts position indicator 170 remains inside breaker 102, enabling full stroke of racking access door stopper 142 in front panel 124, as described below.
FIG. 9A is a front perspective view of interlocking system 136 in the trip position 300 when the breaker contacts are in the open position, FIG. 9B is a rear perspective view of interlocking system 136 in trip position 300, and FIG. 10 is another perspective view of interlocking system 136 in trip position 300 when the breaker contacts are in the open position. When breaker 102 is tripped and the breaker contacts are open, full stroke of racking access door stopper 142 in front panel 124 is possible.
Further movement of racking access door stopper 142 to an open position, which is translated through tripping linkage 146 to actuation slider 148 and further to actuation cam system 150 is possible only when the breaker contacts are open. In such a state, contact position indicator 170 is positioned inside breaker 102 and does not block movement of slider 172, which is acted upon by actuation cam system 150 to move passed contact position indicator 170. Once racking access door stopper 142 is fully pressed in, racking access door 140 can be fully opened providing access to racking screw 128.
When the position of the breaker contacts has been verified, a crank, or other tool, can then be inserted into opening 141 to engage racking screw 128 and subsequently rotated to rotate racking screw 128 and change the position of breaker 102 within assembly 100.
In case of a breaker 102 failure, when the breaker contacts would not be open, but trip signal was provided to breaker mechanism 168 (e.g. the breaker contacts were welded), contacts position indicator 170 will not remain inside the breaker 102. In such a case, movement of slider 172 on side sheet 108 will be blocked. As a result, a full stroke of racking access door stopper 142 will not be possible, and racking of breaker 102 is prevented.
FIG. 11A is a front perspective view of interlocking system 136 in trip position 300 when the breaker contacts are in the open position and breaker 102 is locked, and FIG. 11B is a rear perspective view of interlocking system 136 in trip position 300 when the breaker contacts are in the open position and breaker 102 is locked.
Additional functionality of interlocking system 136 built into front panel 124 is the possibility of locking draw-out assembly 100 such that the position of withdrawable breaker 102 inside base assembly 104 cannot be changed. Safety specifications require that draw-out assembly 100 locking be possible only when breaker 102 main contacts are open and only until breaker 102 reaches its test position (during rack-in). In such a test position, the main contacts of breaker 102 are disconnected from connection terminals 112 in base assembly 104, the secondary circuit of breaker 102 is connected to base assembly 104 allowing tests to be performed on breaker 102, and shutters 114 are closed to prevent access to connection terminals 114.
Verification of breaker 102 main contacts position is performed by fully pressing in racking access door stopper 142 in front panel 124. Once a full stroke of racking access door stopper 142 is possible (which means that breaker main contacts are open), padlock slider 152 can be pulled out from front panel 124 into a lock position. Such movement is possible because racking access door stopper 142 is fully pressed in and is no longer blocking movement of intermediate lever 154, which engages padlock slider 152 and also moves to the lock position. This displacement of intermediate lever 154 prevents the possibility of opening racking access door 140 such that access to racking screw 128 is blocked.
In the above described state, draw-out assembly 100 can be locked by keeping padlock slider 152 pulled out and installing a pad-lock, or by rotating key-lock 156 such that key lock latch 158 engages either intermediate lever 154 or padlock slider 152. When using key lock 156, after locking draw-out assembly 100, the key can be removed.
FIG. 12A is a front perspective view of interlocking system 136 of draw-out breaker assembly 100 when breaker 102 is between the test and connected position, and FIG. 12B is a front perspective view of interlocking system 136 breaker 102 is between the test and connected position.
When racking access door stopper 142 is fully pressed in into front panel 124, which is possible only after positive verification that breaker 102 main contacts are open, and breaker 102 racks-in from test position to connected position, or racks-out from connected position to test position, safety requirements necessitate that it be impossible to close the main contacts of breaker 102. As described herein, the test position is when the main contact system of breaker 102 is disconnected from base assembly connection terminals 112, the secondary circuit of breaker 102 is connected with draw out base assembly 104 to allow tests on breaker 102, and shutters 114 are closed to prevent access to connection terminals 112. Also, the connected position is when the main contact system breaker 102 is connected to base assembly connection terminals 112, the secondary circuit of breaker 102 is connected with draw out base assembly 104, and shutters 114 are open to allow access to connection terminals 112.
Such configurations are possible due to cam 144 being engaged with position indication linkage 138. In between test and connected positions, cam 144, driven by position indication link 138, is positioned to keep racking access door stopper 142 in its fully pressed in position such that a permanent trip signal is provided to breaker mechanism 168 and breaker 102 cannot be closed.
While racking breaker 102 in or out of draw-out breaker assembly 100, locking of draw-out breaker assembly 100 is impossible. Once withdrawable breaker 102 leaves the test position, position indication link 138 blocks possibility of intermediate lever 154 rotation. In such a case, padlock slider 152 cannot be pulled out of front panel 124 and a pad-lock cannot be installed, or key-locks 156 cannot be rotated.
Exemplary embodiments of apparatuses are described herein for use in preventing power from being applied to devices, such as a circuit breaker, when the devices are not fully engaged within a draw-out assembly. These embodiments facilitate safer operation of a circuit breaker. The systems, method, and apparatus described herein facilitate a method for racking a circuit breaker in a draw-out breaker assembly. In particular, the systems, method, and apparatus described herein include an interlocking system that provides a trip signal to the circuit breaker to position a plurality of breaker contacts in an open position. To provide the trip signal, the interlocking system is moved to a trip position. More specifically, an access door stopper is actuated to the trip position, which causes an access door to partially open preventing access to a racking screw, and also causes actuation of a trip assembly to the trip position to engage and rotate a trip bar of the circuit breaker to facilitate tripping the breaker and opening the contacts.
Furthermore, the interlocking system verifies the position of the contacts to confirm that the contacts are indeed open and that a failure has not occurred. In the event of a failure, a contacts position indicator of the interlocking assembly moves from an open position to a failure position and extends from the breaker into the path of the trip assembly. To verify the position, the interlocking system is moved to an open position. More specifically, the access door stopper is actuated to the open position, which causes actuation of a trip assembly to the open position. If there is no failure and the contacts are open, then the trip assembly moves passed and does not contact the contacts position indictor, and the access door is able to fully open allowing access to the racking screw. If there has been a failure and the contacts are closed, the trip assembly will contact the contacts position indicator and prevent trip assembly from further actuation, which prevents the access door from fully opening, therefore preventing access to the racking screw.
The systems, method, and apparatus described herein provide a two-step safety feature during breaker rack-in/out movement. In the first step, a trip signal is provided to the breaker to open the main contact system. In the second step, verification that the main contacts of the breaker are disconnected is performed to protect against any potential failure inside the breaker. The system described herein prevents rack-in/out movement of the breaker when its main contacts are closed. It also provides proper logic of the locking system (key-locking and padlocking), such that draw-out assembly can be locked only if the breaker is in proper position in the draw-out assembly (either the disconnected or test position) and ensures the main breaker contacts are open before locking.
The order of execution or performance of the operations in the embodiments of the invention illustrated and described herein is not essential, unless otherwise specified. That is, the operations may be performed in any order, unless otherwise specified, and embodiments of the invention may include additional or fewer operations than those disclosed herein. For example, it is contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of aspects of the invention.
Although specific features of various embodiments of the invention may be shown in some drawings and not in others, this is for convenience only. In accordance with the principles of the invention, any feature of a drawing may be referenced and/or claimed in combination with any feature of any other drawing.

Claims

A method of assembling a draw-out breaker assembly (100) including a circuit breaker (102) having a plurality of contacts (103), said method comprising:
coupling an interlocking system (136) to a front panel (124) of a base assembly (104), wherein coupling the interlocking system (136) comprises:
coupling an access door (140) to the front panel (124) such that the access door (140) selectively covers an opening (141) formed in the front panel (124);

coupling an access door stopper (142) to the front panel (124) and to the access door (140), wherein the access door stopper (142) is selectively moveable between a rest position, a trip position and an open position; and

coupling a racking screw (128) to the front panel (124) and to the plurality of contacts (103);

coupling a trip assembly (145) to the front panel (124) and to the access door stopper (142), wherein the trip assembly (145) is selectively moveable between a rest position, a trip position and an open position, such that, when (i) the access door stopper (142) is in the trip position, (ii) the trip assembly (145) is moved from the rest position to the trip position by the access door stopper (142) to engage a trip bar (162) of the circuit breaker (102), and (iii) the access door (140) is partially opened such that access to the racking screw (128) through the opening (141) is prevented, a mechanical trip signal is provided to the circuit breaker (102) to position the plurality of contacts (103) in the open position, and such that, when (i) the access door stopper (142) is moved to the open position, (ii) the trip assembly (145) is moved to the open position by the access door stopper (142), and (iii) the access door (140) is fully opened to enable access to the racking screw (128), the open position of the plurality of contacts (103) is confirmed.
The method in accordance with Claim 1, wherein coupling the trip assembly (145) comprises:
coupling a trip bar extension (164) to the trip bar (162) such that moving the trip assembly (145) to the trip position causes rotation of the trip bar extension (164) and the trip bar (162); and

coupling an actuator (166) to the trip bar extension (164) and to a circuit breaker mechanism (168) such that the rotation of the trip bar (162) causes linear movement of the actuator (166) to trip the circuit breaker mechanism (168).
The method in accordance with Claim 1, wherein coupling the access door stopper (142) to the front panel (124) comprises coupling the access door stopper (142) to the front panel (124) such that a portion of the access door stopper (142) extends through the front panel (124).
The method in accordance with Claim 1, further comprising coupling a contacts position indicator (170) to the circuit breaker (102) such that when the trip assembly (145) is moved to the open position, the trip assembly (145) advances past the contacts position indicator (170) in the circuit breaker (102) to enable the access door (140) to fully open.
The method in accordance with Claim 1, wherein coupling the interlocking system (136) further comprises:
coupling a lock link (152) to the front panel (124) such that the lock link (152) is moveable between a locked position and an unlocked position; and

coupling a lever link (154) to the lock link (152) such that the lever link (154) is moveable between a locked position and an unlocked position;

wherein, when the lock link (152) is in the locked position and the lever link (154) is in the locked position, opening of the access door (140) is prevented.
A draw-out circuit breaker assembly (100) including a circuit breaker (102) having a plurality of contacts (103) and an interlocking system (136), said interlocking system (136) comprising:
a racking screw (128) coupled to the plurality of contacts (103) that changes a position of the circuit breaker (102) within the draw-out circuit breaker assembly (100) when engaged by a tool;

a front panel (124) defining an opening (141) through which said racking screw (128) is selectively accessible;

an access door (140) coupled to said front panel (124) and configured to selectively cover the opening (141) to selectively provide access to said racking screw (128); and

an access door stopper (142) configured to limit movement of said access door (140) based on a position of the plurality of contacts (103);

characterized in that said access door stopper (142) is coupled to and at least partially extends through said front panel (124);

and in that said interlocking system (136) further comprises a trip assembly (145) coupled to said access door stopper (142), wherein said access door (140) is moveable between a trip position and an open position, wherein said access door stopper (142) is moveable between a rest position, a trip position and an open position, and wherein said trip assembly (145) is moveable between a rest position, a trip position and an open position,

wherein moving said access door (140) to the trip position, said access door stopper (142) from the rest position to the trip position, and said trip assembly (145) from the rest position to the trip position triggers delivery of a mechanical trip signal to the circuit breaker (102) to open the plurality of contacts (103),

wherein, in the open position, the access door (140) is fully open to enable access to said racking screw (128) through said front panel (124),

wherein, in the trip position, the access door (140) is partially open to prevent access to the racking screw (128) through the opening (141), and

wherein movement of the access door stopper (142) and the access door (140) to the open position is only possible when the plurality of contacts (103) are open.
The draw-out circuit breaker assembly (100) in accordance with Claim 6, wherein said access door stopper (142) and said trip assembly (145) in the trip position provide the trip signal to the circuit breaker (102) to open the plurality of contacts (103), and wherein said access door stopper (142) is fully open to enable access to said racking screw (128) through said front panel (124) in the open position to verify an open position of the plurality of contacts (103).
The draw-out circuit breaker assembly (100) in accordance with Claim 7, wherein said trip assembly (145) comprises a trip link (146) coupled to said access door stopper (142), an actuation slider (148) coupled to said trip link (146), and an actuation cam system (150) coupled to said actuation slider (148), wherein said actuation cam system (150) engages a trip bar (162) of the circuit breaker (102) to provide the trip signal.
The draw-out circuit breaker assembly (100) in accordance with Claim 6, further comprising a contacts position indicator (170) moveable between the open position and a failure position corresponding to the position of the plurality of contacts (103), wherein said contacts position indicator (170), in the open position, enables movement of said trip assembly (145) to the open position and wherein said contact position indicator (170), in the failure position, prevents movement of said trip assembly (145) to the open position.
The draw-out circuit breaker assembly (100) in accordance with Claim 6, wherein movement of said access door stopper (142) to the trip position causes movement of said trip assembly (145) to the trip position.
The draw-out circuit breaker assembly (100) in accordance with Claim 6, wherein movement of said access door stopper (142) to the trip position causes movement of said access door (140) to the trip position.
The draw-out circuit breaker assembly (100) in accordance with Claim 11, wherein movement of said access door stopper (142) to the open position causes movement of said access door (140) to the open position.
The draw-out circuit breaker assembly (100) in accordance with Claim 6, further comprising a lock link (152) moveable between a lock position and an unlock position, wherein said lock link (152) is configured to prevent movement of the circuit breaker (102).
The draw-out circuit breaker assembly (100) in accordance with Claim 13, further comprising a lever link (154) coupled to said lock link (152) and to said access door (140), said lever link (154) moveable between a lock position and an unlock position, wherein, in the lock position, said lever link (154) prevents movement of said access door (140).